experimental FS browsing code. Right now only for POSIX systems, some things not yet implemented, and probably full of bugs

svn-id: r5540

1 files changed, 166 insertions, 0 deletions

diff --git a/backends/fs/fs.h b/backends/fs/fs.h
new file mode 100644
index 0000000000..1dc23abbfd
--- /dev/null
+++ b/backends/fs/fs.h
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+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2002 The ScummVM project
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ */
+
+#ifndef FS_H
+#define FS_H
+
+/*
+ * The API described in this header is meant to allow for file system browsing in a
+ * portable fashions. To this ends, multiple or single roots have to be supported
+ * (compare Unix with a single root, Windows with multiple roots C:, D:, ...).
+ *
+ * To this end, we abstract away from paths; implementations can be based on
+ * paths (and it's left to them whether / or \ or : is the path separator :-);
+ * but it is also possible to use inodes or vrefs (MacOS 9) or anything else.
+ *
+ * NOTE 1: currently ONLY the directory listing mode is used; that is, we only are
+ * interested in listing directories. Thus, for now implementation only have to
+ * list directories.
+ *
+ * NOTE 2: Backends still have to provide a way to extract a path from a FSIntern
+ *
+ * You may ask now: "isn't this cheating? Why do we go through all this when we use
+ * a path in the end anyway?!?".
+ * Well, for once as long as we don't provide our own file open/read/write API, we
+ * still have to use fopen(). Since all our targets already support fopen(), it should
+ * be possible to get a fopen() compatible string for any file system node.
+ *
+ * Secondly, with this abstraction layer, we still avoid a lot of complications based on
+ * differences in FS roots, different path separators, or even systems with no real
+ * paths (Mac OS 9, which doesn't even have the notion of a "current director").
+ * And if we ever want to support devices with no FS in the classical sense (Palm...),
+ * we can build upon this.
+ */
+
+
+#include "common/list.h"
+#include "common/str.h"
+
+class FSList;
+
+/*
+ * A single file system node.
+ */
+class FilesystemNode {
+protected:
+	typedef ScummVM::String String;
+
+public:
+	/*
+	 * The starting point for any file system browsing. Returns a special node
+	 * representing the FS root.
+	 * On Unix, this will be simply the node for / (the root directory).
+	 * On Windows, it will be a special node which "contains" all drives (C:, D:, E:).
+	 */
+	static FilesystemNode *getRoot();
+
+	/*
+	 * Construct a node based on a path; the path is in the same format as it
+	 * would be for calls to fopen().
+	 *
+	 * I.e. getNodeForPath(oldNode.path()) should create a new node identical to oldNode.
+	 */
+//	static FilesystemNode *getNodeForPath(const String &path);
+
+	virtual ~FilesystemNode() {}
+
+	/*
+	 * The display name, used by e.g. the GUI to present the file in the file browser.
+	 */
+	virtual String displayName() const = 0;
+
+	/*
+	 * Is this node valid (i.e. refering to an actual FS object)?
+	 */
+	virtual bool isValid() const = 0;
+
+	/*
+	 * Is this node a directory or not?
+	 */
+	virtual bool isDirectory() const = 0;
+
+	/*
+	 * A path representation suitable for use with fopen()
+	 */
+	virtual String path() const = 0;
+
+	/*
+	 * List the content of this directory node.
+	 * If this node is not a directory, throw an exception or call error().
+	 */
+	virtual FSList *listDir() const = 0;
+
+	/*
+	 * The parent node of this directory.
+	 * The parent of the root is the root itself
+	 */
+	virtual FilesystemNode *parent() const = 0;
+
+	/*
+	 * Return a clone of this node allocated with new().
+	 */
+	virtual FilesystemNode *clone() const = 0;
+};
+
+
+/*
+ * A list of multiple file system nodes. E.g. the contents of a given directory.
+ */
+class FSList : ScummVM::List<FilesystemNode *> {
+public:
+	~FSList()
+	{
+		for (int i = 0; i < _size; i++)
+			delete _data[i];
+	}
+
+	void push_back(const FilesystemNode& element)
+	{
+		ensureCapacity(_size + 1);
+		_data[_size++] = element.clone();
+	}
+	
+	const FilesystemNode& operator [](int idx) const
+	{
+		assert(idx >= 0 && idx < _size);
+		return *_data[idx];
+	}
+
+	int size() const	{ return _size; }
+};
+
+
+/*
+ * Finally, a piece of sample code that does print out the content of your root directory:
+
+void test_FS_stuff() {
+	FilesystemNode *root = FilesystemNode::getRoot();
+	FSList *filesInRoot = root->listDir();
+	
+	printf("Content of your root directory:\n");
+	for (int i = 0; i < filesInRoot->size(); i++) {
+		const FilesystemNode &node = (*filesInRoot)[i];
+		printf("File: '%s', path: '%s'\n", node.displayName().c_str(), node.path().c_str());
+	}
+}
+
+ *
+ */
+#endif